Hello all. I recently bought a 24-channel M-Series console that has been out of commission for at least a decade. The person I bought it from had it in storage (climate-controlled) since he bought it from the Central Office of Information back in the mid-late 90's; it was operational at the time. I'm told that COI had it built for their Radio Studio 1 in the mid-80's, if that rings a bell for anyone.

I'm new to all of this, but looking forward to the challenge of getting this console up and running. I'm pretty much a newcomer to electronics in general, but I'd like to do as much of the work myself as possible so that I really get to know the console inside and out. That being said, I welcome any help that I can get, and I do have a decent-sized budget for parts and to pay for tech time. I'm in Chicago, so if anyone knows of a good tech in the area that has experience with these consoles, that would be wonderful. I have a couple leads that I'm currently following up on. I should also mention that the console did not come with any documentation at all. I'm trying to hunt that down as well.

Here's where things stand right now... I've got all of the modules here with me (channels, routing, faders, meters, etc). I've taken inventory of all the parts, taken pics, and documented the unit numbers. Physically, everything looks like it's in surprisingly good shape. I'm not sure if I'm missing any cards or anything. I don't know enough about the console to be able to tell yet. The frame, stand, and power supplies are in a climate-controlled storage facility. I'm working on getting them moved in. That should happen sometime this month.

First question - can anyone help me with finding documentation? I've contacted Calrec, and they've been very helpful. I need to get them the serial # off of the frame so that they can look for any documentation specific to this console. I've also contacted a couple other people with M-Series consoles who are trying to help as well. The more help the merrier though.

Second question - if given a list of the components and unit numbers, can anyone tell me if I'm missing any parts, specifically cards?

Third and final question (for now anyway :) ) - A local tech gave the following advice on getting started, given that I don't have the frame in-house right now... "Cleaning of all faders, pots, switches, edge connectors, connections, sockets, etc. Before any modules are put into the board, voltages should be checked, then one by one each module put in". Could you tell me what the best way is to do this cleaning? What product(s)/methods should I use? Also, I'm assuming that replacing capacitors or chips is probably not a good idea until I've had a chance to test the modules. Is this true?

HiSo you bought it eh!Does it have LED or 'plasma' bargraphs? I think I was involved in commissioning this console when new but it was a while ago.I certainly did one desk at COI.I would suggest recapping the power supplies at least as you don't want them to fail and possibly trash your modules all at once. They do have overvolts protection but if things get bad it gets messy and expensive!If you can email me some 'intimate' pictures of parts of the desk I may remember more.CALREC are likely to actually have all diagrams but it may be a struggle to get them as it will take a bit of research at their end to sort them out. Most of the circuitry and modules had appeared as variants in other desks of the time so it is only a matter of 'lateral thinking' but it may be time consuming. Small cards go in frames in the back of the desk and should be labelled as to what goes where.Any card with a particular number will fit into any 'hole' e.g. BL1496 (possibly with a version number after).Presets on the cards were set on the bench and should not be 'chasis position' specific. Any gain tweaks would be in the chassis.Matt S

This one has the plasma meters. I'm in contact with someone who used to operate this console at COI back in the 80s, and he told me that the plasmas were not a huge success. He ended up using outboard meters, I believe. It looks like there are only 8 pairs though. The rest of the meters look like they are LED. So it seems like it shouldn't be too bad to replace the plasmas with LED's (hopefully).

Thanks for the tip on the power supplies. I was planning to have these looked at first. These are actually still in storage, so I don't have access to them at the moment, but I do recall that there were stickers on at least a few of the power supplies saying that they were checked as recently as last year. So it's possible that the prior owner had the power supplies looked at and then decided that he didn't want to go through with the full refurb. I'll definitely get them checked though right off the bat just in case.

I've taken pics of every component, and I put together a spreadsheet with unit numbers and descriptions. Someone from Calrec was nice enough to add a column to the spreadsheet with additional notes. I'll PM you with a link to download the ZIP file with all this stuff in it.

I've finally gotten the frame, stand, and power supplies out of storage. Today I was able to take a closer look at the card slots, and it looks like I may be missing 3 cards. I was hoping that someone might know if there is a way to work around the missing cards.

1) Next to the line out cards (2 x LN 1327) there is an empty slot with PFL written on it. I'm assuming that there is a card missing from the slot. Does this have to do with the pre-fade listen?

2) There are 2 empty slots next to the voltage regulator cards in the back that are labeled "DC Converter", so I believe that I'm missing 2 DC Converter cards.

Also, would anyone be able to provide card numbers for the ones that I'm missing? Maybe I'll get really lucky and find replacements on eBay or something. I'm not sure how dependent the particular card types are on the exact desk type, but if it helps, the desk type is M24/1610.

I'll take a look at the back of the two M-Series desks I have in the workshop to see if there is any similarity of card cages, based on your description. I have a full set of cards for a 3rd console, so there is a possibility that I may have what you are looking for.....

HiThe card slots should have the 'name' of the required card written by it.There were often 2 or 3 DC regulator cards to get the 5 Volt 'logic' from the 8 Volt 'lamp' supply.These would be diode fed together so that they 'share' the load.The block schematic would have all the required cards shown on it together with the interconnections. Of course this is unique to your desk so there is a problem if you don't have it. The card frames usually had 'unique' motherboards or 'chunks' of slightly more common configurations such as the 5 Volt regulator area.Matt S

Thanks very much for the replies. Unfortunately, the console didn't come with any documentation. Someone from Calrec is currently looking in the archives for docs that may be helpful, but he's not optimistic given the age of the desk. I've got my fingers crossed though.

On the bright side, the 3 card slots I've mentioned appear to be the only slots with a name/label written on the frame but w/o a card. I've attached pics so that you can get a closer look. Unless I'm misunderstanding Matt's post, it sounds like there is a possibility that my regulator area might match (or be similar to) one of the desks that Gareth has in his shop (thanks for checking Gareth), but maybe the PFL card and the way it's wired up would be unique to my desk. That gives me some hope anyway that a couple of the missing cards can be identified, and hopefully replaced.

Here's a little more info that may help...

In the regulator area, I've got the following slots/cards from left to right (also see pics):

Each of the 5-volt regulator cards has a number written on it that appears to correspond to the position. I guess that only matters for the oddball ZN1441-2 card in the 3rd position.

As far as the missing card in the PFL slot goes, the only additional info I have is that there is a PFL output jack on the back of the console (also see pic).

Thanks again for all the help, and please let me know if I can provide any more details. For instance, I could try to take a look at (and take pics of) the way the missing cards are wired up in the back, if that helps.

HiIt's easy now!The slot with the missing card for PFL should have a 'coding bar' to part identify the card. This is a plastic strip in the back of the board and a corresponding one on the 'socket'. These have 'teeth' which are broken off to identify which TYPE of card fits.This would enable you to find out what should be there. I think it would be a 'mix' type of card so it would have an X as part of it's number, possibly XL1499 (if you have others in there).'DC converters' may have been high voltage converters used to get the 240 Volts for the plasma meters. Look at the witing on the backplane and follow it through to the meter area with a bit of luck. If you are wanting the plasmas you could replace this with an external 240 Volt DC supply (couple of Power one modules perhaps). They are available as a '120 - 200 Volt 150mA version. Wire 2 in series and keep your fingers well away!The 10 Volt regulator card is a.......10 Volt regulator on a card!. I can't remember why your desk would need this reference. It would possiblly be for any automation or maybe the plasma system. Matt S

Hi Adam, I have some M series cards left over from a console break up, though no XL1499s.Don't know if Calrec still have a list of the coding bar letter allocation. Probably thrown out years ago.As Matt says the system diagram usually shows whats what.

Matt, as this desk was slightly before my time, I think, were those regulators used for motorized faders, automation? There are rather alot for an M series. Usually just 2 from recollection.